Exposure to dexamethasone reduces pituitary volume and gonadotropic cell number in rat fetuses

Overexposure to glucocorticoids during the fetal period induces changes in developmental processes in various fetal tissues. The aim of this study was to investigate the effects of the synthetic glucocorticoid, dexamethasone (Dx), on pituitary volume and gonadotropic cells during a critical period of pituitary development. The effects of Dx on stereological parameters of the pituitary gland and FSH and LH cells were investigated in 19 and 21-day old fetuses. On day 16 of pregnancy, the experimental dams received 1.0 mg Dx/kg b.w. subcutaneously, followed by 0.5 mg Dx/kg b.w./day on days 17 and 18 of gestation. The control gravid females received the same volume of saline. FSH and LH cells were stained immunohistochemically by the peroxidase–antiperoxidase method (PAP). In 19-day old fetuses, exposure to Dx caused a significant decrease of pituitary volume, estimated by Cavalieri's principle. Also, the total number of FSH and LH cells per pituitary, determined by physical fractionator counting technique, was significantly reduced. These changes persisted until fetal day 21. Volume densities and numerical densities of FSH and LH cells after exposure to Dx in 19 and 21-day old fetuses remained unaffected. Our results suggest that altered stereological parameters in pituitary gland after exposure to dexamethasone in fetal period could be long-lasting.     

Role of cystatin C and renal resistive index in assessment of renal function in patients with liver cirrhosis

AIM:To evaluate the clinical significance of cystatin C and renal resistive index for the determination of renal function in patients with liver cirrhosis.METHODS:We conducted a study of 63 patients with liver cirrhosis.A control group comprised of 30 age and gender-matched healthy persons.Serum cystatin C was determined in all study subjects and renal Doppler ultrasonography was made.Estimated glomerular filtration rate from serum creatinine(GFRCr)and cystatin C(GFRCys)was calculated.RESULTS:We confirmed significant differences in val-ues of cystatin C between patients with different stages of liver cirrhosis according to Child-Pugh(P=0.01),and a significant correlation with model of end stage liver disease(MELD)score(rs=0.527,P<0.001).More patients with decreased glomerular filtration rate were identified based on GFRCys than on GFRCr(P<0.001).Significantly higher renal resistive index was noted in Child-Pugh C than in A(P<0.001)and B stage(P=0.001).Also,a significant correlation between renal resistive index and MELD score was observed(rs=0.607,P<0.001).Renal resistive index correlated significantly with cystatin C(rs=0.283,P=0.028)and showed a negative correlation with GFRCys(rs=-0.31,P=0.016).CONCLUSION:Cystatin C may be a more reliable marker for assessment of liver insufficiency.Additionally,cystatin C and renal resistive index represent sensitive indicators of renal dysfunction in patients with liver cirrhosis.     

Identification of ginkgolide targets in brain by photoaffinity labeling

Ginkgolides are terpene trilactones in Ginkgo biloba, a popular medicinal herb for memory disorders. Although ginkgolides are known for various neurobiological effects, their macromolecular target in brain is unknown. In this work, we employed benzophenone derivatives of ginkgolides to identify their binding target in brain. Photolabeling of bovine hippocampus homogenates identified a series of α‐tubulin isotypes. Selective photolabeling of α‐tubulin over β‐tubulin, which is equally abundant in brain, suggested that ginkgolides might modulate microtubule biology differently than typical microtubule‐binding agents, such as taxol. In fact, ginkgolide A did not affect microtubule polymerization or cell proliferation; instead, it inhibited detyrosination of α‐tubulin and reorientation of microtubule‐organizing centers. Taken together, the current findings indicate that ginkgolides constitute a new class of microtubule‐binding agents with distinct effects on α‐tubulin biology.     

Biodegradable and plasma‐treated electrospun scaffolds coated with recombinant Olfactomedin‐like 3 for accelerating wound healing and tissue regeneration

Three‐dimensional biomimetic scaffolds resembling the native extracellular matrix (ECM) are widely used in tissue engineering, however they often lack optimal bioactive cues needed for acceleration of cell proliferation, neovascularization, and tissue regeneration. In this study, the use of the ECM‐related protein Olfactomedin‐like 3 (Olfml3) demonstrates the importance and feasibility of fabricating efficient bioactive scaffolds without in vitro cell seeding prior to in vivo implantation. First, in vivo proangiogenic properties of Olfml3 were shown in a murine wound healing model by accelerated wound closure and a 1.4‐fold increase in wound vascularity. Second, subcutaneous implantation of tubular scaffolds coated with recombinant Olfml3 resulted in enhanced cell in‐growth and neovascularization compared with control scaffolds. Together, our data indicates the potential of Olfml3 to accelerate neovascularization during tissue regeneration by promoting endothelial cell proliferation and migration. This study provides a promising concept for the reconstruction of damaged tissue using affordable and effective bioactive scaffolds.     

Segmental-Dependent Intestinal Drug Permeability: Development and Model Validation of In Silico Predictions Guided by In Vivo Permeability Values

The goal of this work was to develop an in silico model that allows predicting segmental-dependent permeability throughout the small intestine (SI). In vivo permeability of 11 model drugs in 3 SI segments (jejunum, mid-SI, ileum) was studied in rats, creating a data set that reflects the conditions throughout the SI. Then, a predictive model was developed, combining physicochemical drug properties influencing the underlying mechanism of passive permeability: Log p, polar surface area, M_W, H-bond count, and Log f_u, with microenvironmental SI conditions. Excellent correlation was evident between the predicted and experimental data (R² = 0.914), with similar predictability in each SI segment. Log p and Log f_u were identified as the major determinants of permeability, with similar contribution. Total H-bond count was also a significant determinant, followed by polar surface area and M_W. Leaving out any of the model parameters decreased its predictability. The model was validated against 5 external drugs, with excellent predictability. Notably, the model was able to predict the segmental-dependent permeability of all drugs showing this trend experimentally. Model predictability was better in the high-permeability versus low-permeability range. Overall, our approach of constructing a straightforward in silico model allowed reliable predictions of segmental-dependent intestinal permeability, providing new insights into relative effects of drug-related factors and gastrointestinal environment on permeability.     

Lack of vitamin D receptor causes stress-induced premature senescence in vascular smooth muscle cells through enhanced local angiotensin-II signals

Objectives

The inhibition of the renal renin-angiotensin system by the active form of vitamin D contributes to the cardiovascular health benefits of a normal vitamin D status. Local production of angiotensin-II in the vascular wall is a potent mediator of oxidative stress, prompting premature senescence. Herein, our objective was to examine the impact of defective vitamin D signalling on local angiotensin-II levels and arterial health.

Methods

Primary cultures of aortic vascular smooth muscle cells (VSMC) from wild-type and vitamin D receptor-knockout (VDRKO) mice were used for the assessment of cell growth, angiotensin-II and superoxide anion production and expression levels of cathepsin D, angiotensin-II type 1 receptor and p57^Kip2. The in vitro findings were confirmed histologically in aortas from wild-type and VDRKO mice.

Results

VSMC from VDRKO mice produced more angiotensin-II in culture, and elicited higher levels of cathepsin D, an enzyme with renin-like activity, and angiotensin-II type 1 receptor, than wild-type mice. Accordingly, VDRKO VSMC showed higher intracellular superoxide anion production, which could be suppressed by cathepsin D, angiotensin-II type 1 receptor or NADPH oxidase antagonists. VDRKO cells presented higher levels of p57^Kip2, impaired proliferation and premature senescence, all of them blunted upon inhibition of angiotensin-II signalling. In vivo studies confirmed higher levels of cathepsin D, angiotensin-II type 1 receptor and p57^Kip2 in aortas from VDRKO mice.

Conclusion

The beneficial effects of active vitamin D in vascular health could be a result of the attenuation of local production of angiotensin-II and downstream free radicals, thus preventing the premature senescence of VSMC.     

Clinical and epidemiological features of Guillain‐Barré syndrome in the Western Balkans

The aim of this study was to define features of Guillain‐Barré syndrome in a large cohort of patients from three Western Balkans countries. Data from adult Guillain‐Barré syndrome (GBS) cases from 2009 to 2013 were retrospectively obtained from all tertiary health care centers. During the 5‐year period, 327 new cases of GBS were identified with a male to female ratio of 1.7 : 1. The most common GBS variants were demyelinating (65%) and axonal (12%). At nadir 45% of patients were chair‐bound, confined to bed, or required assisted ventilation, while 5% died. The crude incidence of GBS in Serbia and Montenegro was 0.93 per 100,000 population, and age‐adjusted incidence according to the world standard population was 0.86 per 100,000. Incidence was particularly high in 50‐ to 80‐year‐old men. Statistically significant seasonal variations of GBS were not observed. This study of patients with GBS in the Western Balkans allows us to prepare the health system better and to improve the management of patients. This study also opens opportunities for international collaboration and for taking part in the multinational studies on GBS.